JamesH, I am going to use the Norma brass, because Richard has informed me it is performing very well out of this chambering and bullet combo.
He also stated he has build about 27 of these exact rifles in the past year, and he explains that all of his customeres are reporting excellent results and amazing accuracy with the Norma brass.
Richard, also stated he is not having any issues with pressures problems or primer pocket issues.
I think one thing to also mention about Richards 300 WSM Varminter, is that he recommends a particular type of barrel and twist rate for this chambering. He recommends the Bartlien, 30", 1-15 twist barrel. He has stated they have all been very consistant with accuracy and velocity with the chambering and bullet combo.
Also, another thing to remeber, he is using the VV-N550 Powder. This powder gives less pressure and gives 100 to 200fps advantage over other powders.
As I mentioned, as soon as I receive the rifle, I will post results and comments. I will be honest, and I will let you know if it works.